Translation guide
In Japanese, irregular conjugation refers to a small set of verbs that do not follow the standard ru-verb or u-verb patterns. The two main irregular verbs are する (to do) and 来る (to come), along with a few others like ある (to be, inanimate) and polite forms. This guide explains how to recognize and use these irregular conjugations.
Explain the conjugation of する and its compounds
The most common irregular verb, meaning 'to do'. Its stem changes across forms.
Many nouns combine with する to form verbs. They conjugate exactly like する.
Explain the conjugation of 来る
The other main irregular verb. Its stem changes between こ, き, く, and くる.
Explain the irregular negative form of ある
Explain the irregular polite forms of the copula
The polite copula です and its past/negative forms are irregular compared to the plain だ.
Explain that some common honorific/humble verbs have irregular conjugations
These honorific verbs are irregular in their ます-stem and imperative forms. The ます-stem ends in い instead of り.
先生はいらっしゃいますか。
Is the teacher here?
どうぞお入りください。
Please come in.
Explain the irregular te-form of 行く
The te-form of 行く is 行って, not *行いて, which is a minor irregularity.
学校に行ってきます。
I'm off to school.
Explain the irregular te-form of 問う
The te-form of 問う is 問うて, not *問って, which is an archaic irregularity still used in formal contexts.
責任を問うて、辞任を求めた。
They questioned his responsibility and demanded his resignation.
Explain the irregular te-form of 請う
The te-form of 請う is 請うて, not *請って, similar to 問う.
許しを請うて、ひざまずいた。
He begged for forgiveness and knelt down.
Focus on mastering する and 来る first, as they are extremely common and appear in many compound verbs.
Most Japanese verbs are regular. Only a handful have irregular conjugations. Avoid applying irregular patterns to regular verbs.